This application is based upon and claims the benefit of priority from the prior Japanese Patent Applications No. 10-011199, filed Jan. 23, 1998; No. 10-241561, filed Aug. 27, 1998; No. 10-248625, filed Sep. 2, 1998; No. 10-248673, filed Sep. 2, 1998; No. 10-295372, filed Oct. 16, 1998; No. 11-012914, filed Jan. 21, 1999; No. 2000-203938, filed Jul. 5, 2000; and No. 2001-000703, filed Jan. 5, 2001, the entire contents of all of which are incorporated herein by reference.
The present invention relates to a high-frequency treatment tool which can grip tissue in a body and coagulate/incise it.
A bipolar forceps is known as a high-frequency treatment tool capable of gripping, coagulating and incising vital tissue. In general, the bipolar forceps has jaws as a pair of gripping members for gripping vital tissue, and high-frequency current supply electrodes formed on the jaws. In this bipolar forceps, when vital tissue to be treated is gripped between the pair of jaws, and a high-frequency current is flowed across the electrodes of the jaws, the vital tissue between the jaws is coagulated or incised.
Bipolar forcipes of this type are disclosed in U.S. Pat. No. 6,024,744, EP 0598348 A1, DE 4032471 C2, and Jpn. Pat. Appln. KOKAI Publication No. 10-199.
The forceps disclosed in U.S. Pat. No. 6,024,744 is a bipolar forceps formed by combining standard surgical scissors with grasping forceps. In this bipolar forceps, a section for coagulating tissue using a high-frequency wave, and a section for mechanically incising tissue are formed in line on the jaws. Since thus, the section for coagulating tissue using high-frequency wave is separate from the section for mechanically incising tissue in the back-and-forth direction, it is necessary to shift vital tissue when mechanically incising the vital tissue after coagulating it using a high-frequency wave. Thus, the operation of the forceps is complicated when performing both coagulation and incision. Further, since the section for coagulating vital tissue using a high-frequency wave is situated at the proximal end side of the jaws, the incising section located at the distal end side of the jaws makes it difficult to coagulate target tissue accurately and delicately.
In a bipolar forceps disclosed in EP 0598348 A1, one of a pair of electrodes is formed of a wire. Using the wire electrode, the forceps incise vital tissue. To coagulate vital tissue, another tool is needed to perform the job.
In a bipolar forceps disclosed in DE 4032471 C2, three electrodes, which include a pair of rod-shaped coagulating electrodes and an incising wire electrode, are used to coagulate and incise vital tissue. Further, the power supply mode is changed between the coagulating electrodes and the incising electrode. Since, in this case, the single wire electrode is used as an incising electrode, and the other rod-shaped electrodes are used as coagulating electrodes, the area needed for the operation of the tool to perform a certain treatment is relatively large, which makes it difficult to perform delicate operations on vital tissue.
Moreover, in this case, three electrodes are necessary, and the power supply mode must be switched between that of coagulating vital tissue and that of incising it. This power switching operation is complicated, which makes it difficult to perform a quick treatment. In addition, the use of three electrodes and the power mode switching between the three electrodes make the electrode structure and power supply structure complicated.
Jpn. Pat. Appln. KOKAI Publication No. 10-199 discloses a technique for rotating, about its longitudinal axis, an electrode member having a coagulation electrode surface and an incision edge electrode, thereby changing the direction of the electrode surface to execute both coagulation and incision of vital tissue. In this technique, when switching the operation between coagulation of vital tissue and its incision, it is necessary to, for example, rotate the electrode member about its longitudinal axis so as to change its direction. Further, when incising coagulated tissue, it is necessary to release the gripped tissue and then to change the direction of the electrode member. Accordingly, the states of the movable jaws must be adjusted by the operation section each time the setting is changed. Thus, operation of the treatment tool is complicated, which makes it difficult to execute a quick treatment. Moreover, to enable the rotation of the electrode member about its longitudinal axis, the electrode support structure and the operation mechanism are necessarily complicated.
It is the object of the present invention to provide a high-frequency treatment tool having an electrode structure capable of treating vital tissue delicately, and performing treating of vital tissue efficiently.
To attain the object, there is provided a bipolar high-frequency treatment tool for gripping vital tissue between two electrically insulated electrode portions, and supplying a high frequency current to the vital tissue gripped between the two electrode portions, thereby coagulating or incising the vital tissue, comprising:
an elongated member;
a pair of jaws provided at a distal end portion of the elongated member such that they can be closed and opened between a closed position and an open position;
an operation unit having a handle provided at a proximal end portion of the elongated member, the operation unit closing and opening the jaws when the handle is operated;
a first electrode portion provided at one of the jaws, and having a first effective electrode surface to be brought into contact with vital tissue when the vital tissue is gripped between the jaws;
a second electrode portion provided at the other of the jaws, opposed to the first electrode portion, and having a second effective electrode surface to be brought into contact with vital tissue when the vital tissue is gripped between the jaws, the second effective electrode surface being smaller than the first effective electrode surface; and
a current supply unit for supplying a treatment high-frequency current to the first and second electrode portions, thereby supplying the treatment high-frequency current to the vital tissue when the jaws are closed to grip the vital tissue between the first and second electrode portions.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.